Compressed air switch with delayed break connector



3 Sheets-Sheet l A. LATOU R May 13, 1952 COMPRESSED AIR SWITCH WI-TH DELAYED BREAK CONNECTOR Filed Jan. 25, 1947 May 13, 1952 A, LATOURy 2,596,254

y coMPREssED AIR swIIcH WITH DELAYED BREAK CONNECTOR Filed Jan. 25, 1947 5 sheets-sheet 2 n Figl A. LATOUR May 13, 1952 COMPRESSE!) AIR SWITCH WITH DELAYED BREAK CONNECTOR Filed Jan. 23, 1947 3 Sheeis-Sheet 5 .A/ y l IZ,

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Lm. @01ML 'Pal-UNG Patented May 13, 1952 COMPRESSED AIR SWITCH WITH DELAYED BREAK CONNECTOR Andr Latour, Grenoble, France Application January 23, 1947, Serial No. 723,728 In France March 8, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires March 8, 1965 6 Claims. l

The present invention relates to a circuit breaker, and more particularly to a circuit breaker of the gas blast type.

In circuit breakers of the kind described it has been suggested to connect temporarily a resistor across the main contacts, the resistor forming part of an electric circuit containing two electrodes separated by a gap. However, the known circuit breakers of this kind have the drawback that the resistor is connected in shunt to the main contacts either too late or too early for an efficient extinction of the arc between the main contacts.

It is an object of the present invention to overcome this drawback.

It is another object of the present invention to start and extinguish an arc between the electrodes forming the gap with a time delay being independent of the main ow of the gas blast.

The present invention consists in a circuit breaker of the gas blast type comprising in ccmbination, a first contact, a second contact arranged movably with respect to the rst contact and being adapted to make contact with the same in one end position thereof, means for directing a gas blast through the arc formed between the contacts upon separation thereof, an electric circuit connected in parallel to the contacts and including in series connection a resistor and two electrodes separated by an arc gap located outside the path of the gas blast acting on the arc between the contacts, and means arranged downstream relating to the first and second contacts for directing a part of the gas blast to the arc gap separating the electrodes, whereby an arc is started and extinguished, respectively. between the electrodes with a time delay being independent of the main flow of the gas blast.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a sectional elevation of a first embodiment of the present invention;

Fig. 2 is a sectional part elevation of a modication of the embodiment shown in Fig. 1;

Fig. 3 is a sectional elevation of another embodiment of the present invention;

Fig. 4 is a sectional elevation of the upper part of Fig. 3 on an enlarged scale, showing a slight modification of Fig. 3;

Fig. 5 is a partial sectional elevation of another embodimentof the present invention; and

Fig. 6 is a partial sectional elevation of a still further embodiment of the present invention.

Referring now to the drawings and rst to Figure 1, the circuit breaker has a stationary rst contact I and a movable second contact 2 which are both designed as hollow tubes and are shown in Figure 1 in the open position thereof. The stationary contact I and the lower part of the movable contact 2 are disposed inside an insulating casing 3 provided with means (not shown) for introducing compressed air at the moment when the contact between the contacts I and 2 is to be broken. The stationary contact I is centered in the casing 3 by means of center pieces such as wings 43. The casing 3 is closed at the top by a metallic body 5 which serves as a guiding member for the movable Contact 2 and supports a terminal 3| being in metallic contact with the movable contact 2 through the metallic body 5. A helical spring 4 is arranged between the terminal 3| and a collar 2 of the movable contact 2 and serves for keeping the movable contact 2 in closed position in which it makes contact with the stationary contact I. The stationary contact I is connected through swinging contacts 'I to a tubular contact member 6 serving as the other terminal of the circuit breaker. The contact members 1 are sliding on the tubular contact member 6 which serves as part of a disconnecting switch interrupting the current connection to the circuit breaker.

An electric circuit is connected in parallel to the contacts I and 2 and includes in series connection a resistor 8 and two stationary electrodes 9 and I0 separated by an arc gap located outside the path of the gas blast acting on the arc between the contacts I and 2. The electrode 9 is arranged inside an insulating casing II having an oriiice I2 being coaxial with the electrodes 9 and I0. The casing II communicates through a conduit I3 with the hollow I4 of the stationary contact I. The electrode I0 is surrounded by an insulating casing I5 leading the ionized gases from the gap between the electrodes 9 and I0 to a cooling device IB comprising parallel blades separated from one another by short distances.

The operation of this device is as follows:

In the closed position of the circuit breaker the contacts I and 2 are in contact with each other. When it is intended to interrupt the current by means of the circuit breaker, the movable contact 2 is moved away from the stationary contact I and an arc is started between the contacts I and 2 which is driven by the gas blast set up in the casing 3 into the hollow interior of the contacts I and 2 through which the compressed air escapes. The interior of these contacts, and especially the discharge channel I4, is traversed by a blast of highly ionized hot gases coming from the arc. From this blast the conduit I3 which is arranged downstream relatively to the contacts I and 2, leads a certain quantity of ionised gas whichn forms a current path between the electrodes Si and I so that'the auxiliary arc strikes. The resistor 8 is thus branched in parallel to the contacts I and 2. When the main arc is extinguished and the pure and insulating compressed air follows the ionised gases in the discharge channel I4, a certain quanty of conducting gas remains in the conduit I3 which has not had time to escape through the orice I2. The resistor 3, therefore, remains shunted between the contacts I and 2 at the moment when the Voltage attempts to re-establish itself between the contacts I and 2 which are thus well protected against any rapid rise in voltage. It is therefore only with a certain lag that the conducting gases contained in the conduit i3 are discharged and replaced by the pure and insulatcompressed air. When the latter in turn escapes through the orifice l2, the conducting path established between the electrodes lll and 9 by the ionised gases is destroyed, the auxiliary arc is extinguished-by the known blast action of the compressed insulating gas and the circuit of the resistor 8 is interrupted. The greater is the volume of the conduit I3 relatively to the section of the aperture l2, the later disappears the conducting path between the electrodes 9 and i9. It is thus possible to regulate at will the duration of insertion of the resistor 8.

In the modication shown in Fig. 2 the blowing blast flow in the casing I y is taken directly from the casing 3 while the conducting path of thermoionic nature is started in the blowing blast flow by the conduit i3 ending at the electrode The stationary contact l and the other electrode ID have the same operation, respectively,` as the stationary Contact i and the other electrode it shown in Fig. 1.

In the case w 1ere the switch rodlike contact associated with hollow contact, the ionised gas can be taken from a vsource situated down stream of the hollow contact. Such an arrangement is shown in Fig. 3 where E indicates the stationary hollow Contact provided with spark arresters il, iii, and 2" indicates the movable rod-like Contact. The latter is connected to the resistor through the intermediary of a sliding contact I t. The ionised gases are collected by means of a collector which opens the conduit i3 feeding the electrode s". If it is desired to obtain a certain pressure the entry oriiice 2l of the collector 23 can be made larger than the outlet orice 22 the collector 2G. The electrode 8 is arranged in an insulating casing and opposite to the electrode Ill" connected to the resistor il.

The ionised gas inlet 2i) can also be arranged as in the modified construction shown in Fig. 1.- comprising a bell-shaped collector 2Q open at the bottom and into the interior of which the conduit I3 penetrates. The latter is closed at its lower part by a plug 23 and a plurality of holes 24 allo-sY the penetration of gas into the conduit I3. Holes 25 are provided at the upper part of the bell-shaped collector 2b to allow the circulation of gas into the annular space between the bell-shaped collector ZEE and the conduit IS". By this arrangement particles from the contacts or the spark arresters are prevented from entering conduit I3".

Instead of taking the ionised gas from the flame of the arc it can be taken from fresh air or gas which is subjected to the ionising action of the radiations from the arc. An embodiment of a device of this kind is shown in Fig. in which the fresh gas is taken from the interior of the casing 3 through a pipe 26 traversing the contact IIV and led through a tube 21 of material permeable to the ionising radiations (quartz for example) which tube is disposed in the eld of the said radiations. 'Ihis tube communicates with a conduit 131V connected to one of the electrodes of the auxiliary arc gap (not shown).

If one of the contacts is a rod-like Contact,

itis also possible to adopt the arrangement shown in Fig. 6 in which IV shows a rod-like contact provided with an end point 2B of refractory material (tungsten, carbon or any special composltion). In this arrangement it suflices to bore in the contact IV a hole 29 opening at the extremity ofV said contact and to branch on this hole 29 the conduit ISV feeding the electrode 9V. The conduit 2) can comprise a closed end 3D serving as trap for metal particles or other impurities. The other parts, such as the insulating casing IIV provided with the orifice l2V and the other electrode IBV connected to the resistor 8V operate in the same manner as the corresponding parts in the other embodiments.

It is obvious that the invention is applicable to all types of known switches no matter what maybe their mode of blowing and independently of the examples given.

It should be understood that any appropriate impedance and particularly a condenser, a condenser shunted by a resistance, an electrolytic or electro-chemical condenser, a resistance varying with voltage, a fuse with automatic regeneration and so on may replace the resistor 8.

Finally, whilst it is not excluded to place the auxiliary arc gap inside the switch, for example inside the discharge passage or at the interior of the casing 3 provided always that the auxiliary arc gap is protected against the direct influence of the main blast flow. t should be understood that the auxiliary are gap may be placed outside the switch. This last arrangement has the advantage of facilitating the maintenance of the circuit oreal-:er and of allowing a particularly easy control of the operation thereof.

What I claim is:

l. A circuit breaker of the gas blast type, comprising in combination, a rst contact; a second contact arranged movably with respect to said first contact and being adapted to make contact with the same in one end position thereof; means for directing a gas blast through the arc formed between said contacts upon separation thereof an electric circuit connected in parallel to said contacts and including in series connection a resistance and two electrodes separated by an arc gap located outside the path of the gas blast acting on the arc between said contacts; and means for directing a part of the 'gas blast to the arc gap separating said electrodes, said means including a conduit and an exit orifice of said conduit having a cross-sectional area appreciably smaller' than the cross-sectional area of said conduit, whereby an arc is started between said' electrodes with a time delay being independent of the main flow of the gas blast.

2. A circuit breaker of the gas blast type, comprising in combination, a first stationary contact; a second contact arranged movably with respect to said rst stationary contact and being adapted to make contact with the same in one end position thereof; means for directing a gas blast through the arc formed between said contacts upon separation thereof; an electric circuit connected in parallel to said contacts and including in series connection a resistance and two stationary electrodes separated by an arc gap located outside the path of the gas blast acting on the arc between said contacts; and means or directing a part of the gas blast to the arc gap separating said stationary electrodes, said means including a conduit and an exit orince of said conduit having a cross-sectional area appreciably smaller than the cross-sectional area of said conduit, whereby an are is started between said electrodes with a time delay being independent of the main flow of the gas blast.

3. A circuit breaker of the gas blast type, comprising in combination, a first Contact; a second contact arranged movably with respect to said iirst contact and being adapted to make Contact with the same in one end position thereof; means for directing a gas blast through the are formed between said contacts upon separation thereof; an electric circuit connected in parallel to said contacts and including in series connection a resistance and two electrodes separated by an arc gap located outside the path of the gas blast acting on the arc between sai-d contacts; and means for directing a part of the gas blast to the arc gap separating said electrodes, said means including a conduit, a gas-collecting device arranged at the entry of said conduit and an exit orifice of said conduit having a cross-sectional area appreciably smaller than the cross-sectional area of said conduit, whereby an arc is started between said electrodes with a time delay being independent of the main iiow of the gas blast.

4. A circuit breaker of the gas blast type, comprising in combination, a rst contact; a second contact arranged movably with respect to said first contact and being adapted to make contact with the same in one position thereof; means for directing a gas blast through the arc formed between said contacts upon separation thereof; an electric circuit connected in parallel to said contacts and including in series connection a resistance and two electrodes separated by an arc gap located outside the path of the gas blast acting on the arc between said contacts; and means for directing a part of the gas blast to the arc gap separating said electrodes; said means including a conduit, a gas-collecting device arranged at the entry of said conduit and having an additional outlet orice other than the entry opening of said conduit and an exit orice of said conduit having a cross-sectional area appreciably smaller than the cross-sectional area of said conduit, whereby an arc is started between said electrodes with a time delay being independent of the main flow of the gas blast.

5. A circuit breaker of the gas blast type, comprising in combination, a rst contact; a second contact arranged movably with respect to said rst contact and being adapted to make contact with the same in one end position thereof; means for directing a gas blast through the arc formed between said contacts upon separation thereof; an electric circuit connected in parallel to said contacts and including in series connection a resistance and two electrodes separated by an arc gap located outside the path of the gas blast acting on the arc between said contacts; and means for directing a part of the gas blast to the arc gap separating said electrodes, said means including a conduit, a gas-collecting device arranged at the entry of said conduit and an exit orifice of said conduit having a cross-sectional area appreciably smaller than the cross-sectional area of said conduit, said conduit having a sealed end arranged inside said gas-collecting device and holes provided in the conduit wall near said sealed end, whereby an arc is started between said electrodes with a time delay being independent or the main ow of the gas blast.

6. A circuit breaker of the gas blast type, comprising in combination, a iirst contact; a second contact arranged movably with respect to said rst contact and being adapted to make contact with the same in one end position thereof; means for directing a gas blast through the arc formed between said contacts upon separation thereof; an electric circuit connected in parallel to said contacts and including in series connection a resistance and two electrodes separated by an arc gap located outside the path of the gas blast acting on the arc between said contacts; and means for directing a part of the gas blast to the arc gap separating said electrodes, said means including a conduit and an exit orice of said cono duit having a cross-sectional area appreciably smaller than the cross-sectional area of said conduit, said conduit including a portion consisting of a material permeable to ionizing radiation and arranged in the path of the radiation of the arc formed between said contacts, whereby an arc is started between said electrodes with a time delay being independent of the main flow of the gas blast.

ANDR LATOUR.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED S'lATES PATENTS Number Name Date 2,275,872 Trencham et al. Mar. 10, 1942 2,349,095 Henley May 16, 1944 2,367,934 Flurscheim Jan. 23, 1945 2,391,826 Flurscheim Dec. 25, 1945 2,441,943 Bruhlmann May 18, 1948 2,453,555 Thommen Nov. 9, 1948 FOREIGN PATENTS Number Country Date 538,672 Great Britain Aug. 12, 1941 

